1. Field of the Invention
The invention relates to a foldable bicycle crank; more particularly, the invention relates to a foldable bicycle crank in which a crank head can be quickly and conveniently bent and rotated by an angle, so as to effectively secure the crank no matter whether the crank head is unfolded or folded.
2. Description of Related Art
The transverse area occupied by a normal bicycle is significantly expanded by the vertically arranged crank and pedals protruding from the body of the bicycle. When the bicycle with the pedals is not ridden but moved, the protruding pedals are very much likely to get stuck with other objects and may cause inconvenience to storage and package of the bicycle during transportation. Currently, folding mechanisms are often arranged on the pedals to resolve said issues. With said mechanisms, the foldable pedals are bent by 90 degrees in an upward direction or in a downward direction, and the upright pedals lean against the outer side of the crank; thereby, the transverse width of the bicycle is increased, and the purpose of minimizing the volume of the folded bicycle crank cannot be achieved. In addition, the folding mechanisms are not reliable and may easily be loosened, which frequently discomfort the user.
A conventional foldable bicycle crank, as disclosed in U.S. Pat. No. 6,637,292 invented by the inventor of the invention described herein, is a foldable and rotatable crank that can be pivoted and rotated by 90 degrees and located at the inner side of the crank, so as not to increase the transverse width of the bicycle. However, the folding operation requires both hand of the user, and the structural design of the conventional foldable bicycle crank is complicated and costly. Hence, further improvement may be needed. Besides, other crank structures that can be applied to fold the pedals of a bicycle often require assistant tools, significant operational time, and/or complicated set-up processes, and thus improvement of the existing crank structures is expected as well.